Molded records, such as conventional audio records and the more recently developed high density information discs, including capacitive electronic discs and optical discs, are mass produced by the same general procedure. The initial step is to record the signal information desired to be reproduced in the molded record or disc on a magnetic tape. The magnetic tape is then used to control a recording apparatus which forms a spiral information track containing the signal information in a substrate.
Once the substrate is recorded, it is used as a matrix on which to electroform one or more replicas referred to as masters which are negative replicas of the recorded substrate. A suitable metal, such as nickel, is electrodeposited on the recorded substrate in an amount sufficient to form self-supporting masters. The masters are then used as matrixes on which to electroform a series of replica parts referred to as mothers which are positive replicas of the recorded substrate. Each of the mothers is in turn used as a matrix on which to electroform a series of parts referred to as stampers which are negative replicas of the recorded substrate. It is the stampers which are eventually used in a molding process to press the signal information originally recorded in the substrate into the molded record or disc.
Considerable problems are encountered in the electroforming which can adversely affect the quality of the molded records or discs. The matrix to be replicated, albeit, a recorded substrate, master, or mother, is attached to a cathode head assembly and is then immersed in an electrolyte bath. During electroforming, electrolyte often leaks to the back of the matrix being replicated and causes a variety of problems including a condition known as "back plating," which results in metal being deposited on the back surface of the matrix which can damage the matrix and cause highly undesirable distortion of the recorded surface.
Most of the problems encountered as a result of leakage of electrolyte can be traced directly to the cathode head assemblies employed in electroforming and/or operator error mounting the matrix on the cathode head assemblies. The cathode head assemblies typically employed in the prior art have a casing or support made of a dielectric material, such as rubber, on which the matrix is mounted, with electrical contact being made between the matrix and the cathode of the electroforming apparatus.
What would be highly advantageous would be a cathode head assembly which, when assembled, would consistently provide an electrolyte tight seal of a matrix to be replicated to the cathode head and which after electroforming of a replica on a matrix could readily be disassembled for removal of the replica from the matrix without damage to the matrix or replica.